[SOLVED]820-2936 No pictures

[Glenn]

Hello.

I have receive a 820-2936B board that don't show anything on the screen only backlight running.
Wher do i start on this one? i have no idea what happened with the card before i get it. it`s no since to water damage.
(the happy apple sound come on startup)

Thanks for all help

Regards
Glenn

 

[dukefawks]

Getting 3V on both sides of L9004?
Did you do a PRAM reset? Disconnect everything besides the LCD?

 

[Glenn]

Sorry for late replay. on L9004 i only get 0.279V
Yes i have tray a PRAM reset and that doesn't helps.
Have disconnected all expect the LCD and still get 0.279V

 

[Glenn]

but i think i have a short on that line... when i put red prob on ground and black on L9004 pin1 in diode mode i get OL

 

[Glenn]

Think i have a broken U9000. When i put the black prob on ground and the red on u9000 pin 5 i get pictures on the screen so hopefully it is only to change that i hope.

(when i measuring from ground to to u9000 pin 6 i get 0,468 and no piiiiiiiiiiiiiiiiiiiiip but if i press the prob down on the board it say piiiiiiiip)

 

[Glenn]

Have replace the u9000 and now all is OK!

 

[Glenn]

But i have 2 more board off this type. They only show backlight and nothing more. I have 3.3v all way too the lvds connector. Have disconnected all exept keyboard, fan and screen. Have tray a PRAM reset. when i measuring in diode mode on u9000 pin 1-5 i get 0,132

 

[dukefawks]

They show backlight with a "darkish" not white screen?

 

[Glenn]

Yes its more gray/darkish then white. Its like the photo on the first post.

 

[dukefawks]

Measure all LVDS lines on diode mode, pin 8-18.

 

[Glenn]

Pin8 0.604
Pin9 0.604
Pin10 0.000
Pin 11 0.605
Pin12 0.605
Pin13 0.000
Pin 14 0.586
Pin15 0.606
Pin 16 0.000
Pin17 0.606
Pin18 0.606

 

[Glenn]

Have also tried new lcd with new cable.

 

[Glenn]

If i run extern screen whit from thunderbolt screen the extern screen show pictures. (When disconnected the internal screen)

 

[dukefawks]

As you can see pin 14 is the odd one out, this is a dead PCH. You will need to replace the PCH and flash a clean ME region. You can upload your original ROM here and I can fix it.

You said you had 2 boards? What are the values on the other one, don't assume the PCH is also dead.

 

[Glenn]

Sorry dukefawks im pretty new in board repar and realy dont know what PCH is and have no idea how to take copy or flash ME region.

On the other board i found 3 fucked components L9004 is blow away whit the pin on the board and c9010 and L9008 is burned.

I will not touch the other board befor i have fixed the second one.

 

[dukefawks]

The PCH is U1800 and you need programmer to read/flash the ROM like TL866 or EZP2010.

 

[Glenn]

Ohh that sounds really hard for a newbie to do..
But no after replacing u9000 i get 0.605 on pin 14.

How do I actually remove the u1800? Hot air? How do I replace it? Rebelling?

(And the backlight feel more withe and not grey ish)

 

[Glenn]

Will take a new photo off the screen tomorrow

 

[dukefawks]

Replacing U9000 because of pin 14???? what where?? What are you doing? The PCH is dead!

You beed a BGA rework station and experience. These are not boards to practice on, get a trash PC laptop board and practice BGA rework on that.

 

[larossmann]

u9000 doesn't attach to pin 14. the 820-2936 is a $250 board, which isn't worth a $30 chip, 45 minutes of BGA work, and the risk that the chip you bought is bad/not the only problem.